Gas analysis
Gases were collected over water (pH adjusted to 2
to avoid CO2 dissolution) in graduated aspirator
bottles and volumes calculated at 25°C. The contribution
of the cattle-dung inoculum towards the
biogas yield was also taken into consideration (Kalia
et al., 1992a). Hydrogen, CH4 and CO2 were analysed
by standard GC procedures on a GC 5700
(Nucon Engineers, New Delhi). Argon was used as
the carrier gas. Hydrogen sulphide was determined
by passing the gas sample through 10% lead acetate
solution (Kalia et al., 1992a; 1994)